Engine accessories, such as an alternator, an air compressor, an air conditioning compressor, a water pump, an oil pump, and so on are generally driven by the engine. In one situation, in order to extend an engine life, reduce fuel consumption, limit emissions, and so on, the engine may be shut off instead of running the engine at an idle speed. As a result, the engine powered accessories may also stop and may require an engine restart in order to power the accessories alone. Alternatively, the accessories may be designed to be electrically driven. However, such an arrangement may require a dedicated electrical power source in turn increasing system cost, service/replacement cost, system bulk, packaging complexity, and so on.
Typically, a flywheel is employed in order to suppress oscillation in torque and/or speed of the engine resulting from sequential firing of cylinders of the engine. During operation of the engine, a number of applications may subject the engine to a load in excess of a rated power of the engine. In such a situation, inertia/kinetic energy of the flywheel may be used in order to compensate for the excess load demand. However, there are practical limits to the amount of kinetic energy that may be stored in the flywheel. The limitations may include a packaging space, a journal bearing capacity for overhung load, resistance to engine starting, and so on.
U.S. Pat. No. 4,372,262 describes an apparatus for stopping and restarting a motor vehicle by means of a flywheel. The flywheel is alternately clutched to an engine crankshaft to be driven thereby or declutched to rotate freely for subsequent driving of an engine to restart the engine. The engine is shut off in response to release of an accelerator pedal deactivating switches controlling a clutch mechanism after a predetermined time delay longer than a time normally required for a gear shift change.